Neutrons have been a useful probe in many fields of science as well an an important physical system for study in themselves. Modern neutron sources provide extraordinary opportunities to study a wide variety of physics topics. Among them is a detailed study of the weak interaction. In this talk, I will present an overview of studies of the hadronic weak (quark-quark) as well as semi-leptonic (quark-lepton) interactions and discuss what physics we hope to learn through the program on the Fundamental Neutron Physics Beamline at the Spallation Neutron Source.